Elevator inductor switch



Jan. 12, 1954 c. SAVAGE ELEVATOR INDUCTOR SWITCH Filed May 20, 1950 Fig.|.

Insulation Patented Jan. 12, 1954 ELEVATOR INDUCTOR SWITCH Conwell Savage, New York, N. Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 20, 1950, Serial N0. 163,291

9 Claims. l

This invention relates to electromagnetic devices, and it has particular relation to inductor switches suitable for use in controlling the operation of electrical elevators.

Inductor switches or relays have been employed widely in the control of electrical elevators. As an example of an elevator control system employing inductor switches, reference may be made to the Mattingly Patent 1,884,514.

For eilicient operation of an elevator system, an inductor switch should initiate a slowdown or stopping operation at a predetermined distance from a oor at which an elevator car is to stop. The accuracy of the inductor switch should not be aiiected by lateral movements of an elevator car in its hoistway. Similar comments apply to inductor switches employed for releveling an elevator car at a floor. In the Harry Berkovitz patent application, Serial No. 129,665, filed November 26, 1949, and assigned to the same assignee, an improved relay structure is provided. Berkovitz employs magnetic channels as inductor plates. Each channel extends in a direction parallel to the path of travel of the elevator car. The Berkovitz inductor switch employs a coil mounted with its axis transverse to the direction of travel of the elevator car. This coil has a magnetic structure which includes a pair of spaced polar magnetic plates which denne a nonmagnetic gap therebetween. When the coil is energized, the polar plates are excited with opposite magnetic polarities to produce a magnetic iield in the non-magnetic gap. Each polar plate may have a slot within which a magnetic armature is positioned for movement toward and from the non-magnetic gap. Each magnetic armature thus is eiectively shielded by its associated polar plate.

During the travel of the elevator car in its hoistway, a channel enters the non-magnetic gap and has each of its flanges adjacent a separate one of the polar plates. The magnetic reluctance between the polar plates thus is substantially reduced, and sufcient magnetic iiux flows to actuate the magnetic armatures. polar plates are offset from the axis of the coil to permit the inductor switches to be stacked in the direction of travel of the elevator car for successive operation within a short distance by a common channel.

In accordance with the invention, an inductor switch of the general type disclosed in the aforesaid Berkovitz application is provided with an improved armature and polar plate construction. magnetic forces acting between the polar plates and the armatures with a resultant increase in eiiiciency of operation. Shielding also is improved.

In addition the invention provides enclosures Preferably, the f This improved construction reduces the for the armatures and the contact assemblies operated by the armatures. The enclosures protect the armatures, air gaps and contact assemblies with no impairment in operation thereof.

The invention also comprises improved links associated with the armatures for operating the associated contact assemblies. Connections between the links and the associated components are effected by simple key and keyhole connections which facilitate construction and servicing of the equipment and which assure negligible friction for the moving parts.

It is, therefore, an object of the invention to provide an improved, simple and sturdy inductor switch which has negligible friction between moving parts.

It is a second object of the invention to provide an inductor switch having an armature movably associated with a polar plate and having an air gap between the armature and the polar plate which minimizes magnetic forces therebetween.

It is a third object of the invention to provide an inductor switch having an improved protective enclosure.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a top plan view with parts in section of an inductor switch embodying the invention;

Fig. 2 is a view in side elevation with parts broken away of the inductor switch shown in Fig. 1;

Fig. 3 is a view in side elevation of a rst link employed in the inductor switch of Fig. 1;

Fig. 4 is a View in side elevation of a second link employed in the inductor switch of Fig. 1; and

Fig. 5 is a detail view in plan of a portion of an arm employed in the inductor switch of Fig. 1.

Referring to the drawing, Fig. 1 shows an inductor switch I associated with an inductor plate P. The inductor plate P is in the form of a channel having flanges PI and P2.

When employed for controlling an elevator system, one of the inductor plates P would be positioned in the hoistway of an elevator car for each of the floors served by the elevator car. The inductor switch l would be secured to the elevator car for movement therewith. As shown in Fig. 2, the inductor switch l would move with the elevator car in the direction of the arrows 3 along a path parallel to the inductor plate P.

The inductor switch l includes a base structure 5 which is constructed of non-magnetic material. This base structure supports a magnetic structure l which denes a large non-magnetic air gap for reception of the inductor plate P.

The magnetic structure 'l includes a magnetic core 9 which is located within a coil il. Polar assemblies I3 and i5 are secured to the respective ends of the core 9.

The polar assembly i3 comprises a plate E? which has a slot i@ therein. A magnetic armature 2l is located in the slot for movement about an axis towards and from the air gapwithin which the inductor plate P is received. Y

The magnetic armature 2i may be pivotaliy mounted with respect to the-plate Il inany'suit- :magnetic V'or:magnetic material. Abronze spring ribbon 1has'been found to fbe satisfactory Tor 'the :spring 2-3.

lvlovernent of the Mmagnetic 'armature El is inftended to operate va switcher contact assembly f25. The 'switch assembly :includes an .electro-conductive leaf spring 2? zwhich fhas alcontact ibut-- itonr291adjacent one tend thereof. This vcontact rbutton :cooperates with 1a lcontact Ybutton .3i Asecuredato one aend of aan'electroconductive strip The spring 2l and the strip 3? are secured'to the .base structure-5 butareinsulated irom'each other .inzany :suitable manner. For example, insulating spacers 35 vmay he employed for insulating fthe `rspring .and strip from Yeach other and from the ,base structure.

-order to Aoperate :the iswlitch assembly, an .arm -3-l is secured to .the magnetic armature This arm has a lip 39 which is substantially par- ;allel .to .but spaced from k.the spring 2.. Aiinl; il .isiemployed for connectingitherlip 'f'S tothe spring 2 which serves las an operating nicirlber for the switchassembly.

-As1shown fmoreclearlyin lFig. 4, .the liniaal is formed of a sheet of insulating material, suchras .ra phenolic resin, and has y'a double keyhole slot formed therein. This .double 'keyhole slot includes a large opening la which forms a common ;par.t of 'the twokeyhole slots. The .-largecpening 41a communicates Iwithftwo ioppositeiy vdirected fsmallfopenings lzb and ille.

By comparing Figsfeand .it avillfbe-noted that the lip 33 has a key formation. The key is :de- .dned byftwo notches tea vand :3% .which provide a head Sec proportioned to lpass `through. the opening die, but too large to pass through the -srnall openings flll'b and Pdie. fIn addition ithe matches `denne a neck V39d which lis proportioned .for .reception .in lone tof the small openings #AI b .or Mc. Consequently .the zlip 39 may fbe :introduced 'through the openingfl id of the link 14H and v.then .fmove'dgat right .angles :relativeito ythe.linkato-r the .purpose :ofrinoving zthe neck .39d Aanto one of the zsrnall rop eni-ngs dal b v'or'ai c.

.llnaa similar manner, the left-handend of the. spring A2"? i(as viewed in Fig. .'1) .is constructed vas .9, key having a head 255e anda neck 2id proportioned for :reception in one Vof the small openings of the associated link-ill.

The bias exerted by vthe spring .2 is ina direction tending to move the spring away Vfrom the lip v39. The bias exerted by the-spring 23-on :the :armature :2l rand the llip 39 is in a direction tending to move vthe lip awayzfromthe spring 2l'.

'This tends Yto hold the .flip :and the :spring El in the small openings of the associated link i. At the same time, the link has suilcientplay to provide la hinge action between the .link and the lip 3S and between the link and the spring 2l. Fcr this reason forces are transmitted between the Amagnetic armature 2l and the spring 2'! with negligible:friction It will be noted that the bias exerted by the spring 2l urges the buttons 2S and '3| intoengagement with each other.

In'order to vprotect the magnetic armature 2| and the associated switch assembly, a non-magnetic sheet may Ybe secured over the slot i9 in any suitable manner. For example the sheet e3 may be Vconstructed from sheet brass and may be brazed to the plate il.

In Aaddition a coverr'll'is 'tprovided Donveniently this vcover may .be constructed of nonvmagnetic material. The cover is proporticnedzto engage the base structure 5 and the :plate 13ste complete fan enclosure 'for the magnetic 'armature A2%! :and the:associated :switch` assembly. 'The'.cover emay be detachably :secured to the `.base 'structure and the plate ll `in any suitable manner ias rby machine Yscrews ll'.

'By inspection oi SFi'g. l, it will berobserved `that "the sheet it iserves :as a stop limiting `.travel :of Lthe magnetic armature inrone idi-rection. 'Travel of the .armature in the .opposite -direction may be 'limited 'by means offaribfi'l which-is anzintegral 'part/ortho structure ofthe cover-45.

It will 'be :understood that `suitable iconductors .151i andlare provided for vconnecting therspring '121i and the 'strip if) tofan externalfcircuit.

The polar assembly i5 includesialplate 511i :zh-aving a vslot 15'! within which .a .magnetic armature 59 ispositioned for pivotal movement relativeto the .plate :55. A nonemagnetic :sheet 61 :is :emfployed for covering .the 'slot T51. A cover '63 is .provided'to complete :an enclosure for .the maignetic armature. The plate .55, the .magnetic armature 59,1.the sheet-.G11 andthe .cover 63 are similar respectively to the .plate l1, the xmasnetic Varmature .'21, the sheet :4.3 and the 'cover fwhich are described abovefbut :it will :be noted that .the polar assembly 15 `is reversed relative .to `the polar assembly -:I3 about -an vaxis transverse to the axis of the coil. Themagnetic armature '59 Vlis pivotallya'ssociatedwith .thegplater in the vsame manner by which the lmagnetic:armature 2-l is associated with theplate Il..

,An electrical 4switch or contact assembly l[l5 -is associated with the ymagnetic armature :59. This switch assembly may be similar in enstruction and :operation to the switch assem- -bly 25. However, .in the `specic .embodiment Yof Fig. .1, the switch .assembly is @of the rmakeor contact-.closing type .as contrasted with .the .break or vcontact-.opening type represented .by the switch assembly .z2 5.

The switch :assembly includes ra -leaf :spring l:5.7 having acontact .button 59 at one end. This y.spring and the .button .may .be .exactly similar .to

rthe .spring .2.1 and vthe button .29 previously discussed.

The spring 51 and the button :'lfcnoperatewith .an felectroconduotive strip 'H :and a -contact .button 13. The `strip ll! 'and the'spring -61 Iare insulated Yfrom each other fand are :secured :to vthe a ase structure 5 .in `the 'samemanner by which the spring 27 and strip :3'3 are'secured to the base structure.

The magnetic :armature :5S .has associated .therewith :an arm .'15 l'having .a lip 'H which cnrv responds to the arm 3'! and the lip 39 previous- .L1-y ldescribed. A link 19 `fis employed :for =trans nitt'iig forces between the spring E1 and the As shown in Fig. 3, the link 19 has two small openings 19h and 19e which correspond to the openings -4Ib and 4|c of Fig. 4. However, the link 19 has a large opening 19a which is much longer than the opening 41a of Fig. 4 and has a bridge 19d which divides the opening 19a into two portions. The spring 61 and the lip 11 are associated with the link 19 in the same manner by which the spring 21 and the lip 39 are associated with the link 4I. However, by inspection of Fig. 1 it will be observed that the strip 1| extends through the opening 19a above the bridge 19d. Consequently when the link 19 moves in an upward direction, as viewed in Fig. 1, the bridge 19d engages the strip 1I to serve as a stop limiting further motion 0f the link relative to the strip.

The bias exerted by the spring 61 is in a direction urging Ithe button 69 away from the but- .ton 13. The bias exerted on the armature 59 by the associated hinging spring is in a direction urging the lip 11 away from the spring 61.

It is believed that the operation of the inductor switch now may be set forth. As long as the coil II is deenergized, no magnetic ilux is supplied to the magnetic structure, and the switch assemblies remain in the positions illustrated. Movement of the inductor plate P between the polar assemblies I3 and I5 consequently has no eiect on the inductor switch. When the coil I I is energized, a magnetomotive force is established between the polar assemblies I3 and I5. If the inductor plate P is displaced from the inductor switch, a substantial air gap exists between the magnetic armatures 59 and 2| and the magnetic forces acting thereon are extremely small. Consequently the energization of the coil III has no eiiect on the switch assemblies as long as the inductor plate P is displaced from the inductor switch.

When the inductor plate P enters the gap between the armatures, the magnetic reluctance offered to the flow of magnetic ux produced by current flowing in the coil I I is materially reduced and substantial forces act on the magnetic armatures urging them towards the inductor plate. The magnetic armature 2| is urged from the position illustrated in full lines in Fig. 1 towards the position illustrated by the dotted line. In moving, the magnetic armature 2| operates through the link 4I to separate the buttons 28 and 3|. This interrupts any circuit which is completed through the buttons 29 and 3|.

At the same time the magnetic armature 59 moves towards the flange PI. Such movement operates through the link 19 to move the button 69 into engagement with the button 13. The engagement of the buttons 69 and 13 may be employed for completing any electrical circuit connected to the spring 61 and the strip 1I.

Inasmuch as each of the magnetic armatures moves with respect to its associated plate, such movement may change the magnetic forces acting therebetween. To minimize such changes in magnetic forces, the air gap between each magnetic armature and its associated magnetic plate is larger at a substantial distance from the spring 23 than for a lesser distance from the spring 23. For example, as shown in Fig. 2, the slot I9 may have a substantially trapezoidal configuration which is defined by walls I1a, |11), I1c and Hd. The magnetic armature 2i, as shown in Fig. 2, has a rectangular outline. By inspection of Fig.

2, it will be noted that the spacing or air gap between the magnetic armature and the left-hand wall I1a is comparatively large. The walls |1b and Id also are substantially spaced from the left-hand end of the magnetic armature as viewed in Fig. 2 and gradually approach the magnetic armature at points closer to the spring 23.

The effect of this construction of the slot is such that most of the magnetic Iiux passing between the magnetic armature and the associated plate I1 crosses the air gap therebetween at points which are comparatively close to the spring 23. The forces produced by such magnetic flux for the most part have small torque arms acting about the hinge established by the spring 23. For this reason the torque which results from movement of the magnetic armature 2| relative to the plate I 1 is minimized.

Furthermore, by inspection of Fig. 1, it will be observed that the right-hand end of the magnetic armature 2| does not move appreciably with respect to the associated plates I1. This is for the reason that the right-hand end of the magnetic armature is adjacent the hinge axis established by the spring 23. Since most o the flux passing between the magnetic armature and the plate l1 flows through an air gap which does not change appreciably in position, it follows that the change in the magnetic forces resulting from such small variations in the air gap are also comparatively small.

It will be noted that the magnetic plate I1 completely surrounds the magnetic armature in a plane parallel to the direction of movement of the inductor switch relative to the inductor plate P. For this reason the inductor switch detects accurately the approach of the inductor plate from either direction.

Although the invention has been described with reference to certain specific embodiments thereof, numerous modications falling within the spirit and scope of the invention are possible.

I claim as my invention:

l. In an electromagnetic device, an electricallyenergizable coil, a magnetic structure establishing a path having a non-magnetic gap for magnetic ux produced by current owing in the coil, said magnetic structure comprising a magnetic core disposed in the coil, a magnetic polar structure adjacent an end of the magnetic core, said polar structure having a slot extending therethrough, a magnetic armature disposed in said slot for movement relative to the polar structure about an axis towards and from the non-magnetic gap, the polar structure and the magnetic armature being disposed on one side of the nonmagnetic gap, said magnetic structure having an air gap between the polar structure and the magnetic armature which is larger at a distance from said axis than at a position closer to said axis.

2. A device as claimed in claim 1 wherein the magnetic armature is of substantially rectangular configuration and said slot is of tapered construction with the small end of the slot closer than the large end of the slot to said axis.

3. A device as claimed in claim 1 wherein the magnetic polar structure substantially completely surrounds the periphery of the magnetic armature.

4. In an electromagnetic device. an electricallyenergizable coil, a magnetic structure establishing a path having a non-magnetic gap for magnetic flux produced by current flowing in the coil, said magnetic structure comprising a magnetic core disposed in the coil, a magnetic polar structure adjacent an end of the magnetic core, said polar structure having va slot extending therethrough, a magnetic armature disposed in said slot for movement relative to the polar structure about `an axis towards and from the non-magnetic gap, the polar structure and the magnetic armature being disposed on one side of the nonmagnetic gap, said magnetic polar structure extending in a plane parallel to said axis around four sides of the magnetic armature to provide effective magnetic shielding in said plane for the magnetic armature.

5. In an electromagnetic device, an electricallyenergizable coil, a magnetic structure establishing a path having a non-magnetic gap for magnetic` flux produced by current owing in the coil, said magnetic structure comprising a magnetic core disposed in the coil, a magnetic polar strncture adjacent. an end of the magnetic core, said polar structure having a slot extending therethrough, a magnetic armature disposed in said slot for movement relative to the polar structure about an axis towards and from the non-magnetic gap, the polar structure and the magnetic armature being disposed on one side of the nonm'agnetic gap, contact structure comprising contacts operated by said armature, and enclosing Structure providing a substantially sealed enclosure for the armature and the contact structure, said enclosing structurev including a iii-st non-magnetic cover for said slot, said cover being interposed between the magnetic armature and saidr non-magnetic gap, and a second cover detachably secured to the polar' structure, said polar structure constituting a part of the enclosing structure.

6. In a magnetically-operated device, a source of magnetomotive force, a magneticl structurev de'- iining a magnetic path having a non-magnetic gapl for magnetic flux producedy by saidl source, said magnetic structure including a magnetic polar plate having a surface abutting said gap, the polar plate having an' aperture communicating with the gap, a magnetic armature disposed substantially in said aperture in spaced relationship relative to the Walls of the aperture, means mounting the magnetic armature for. movement relative to the' polar plate about an axis towards and from the gap, the'gap between thepolar plate andV the armature being greater at pointsI asubstantial distance from the axis than at points closer to the axis, and translating means responsive to movement of the armature relative to the polar plate.

7.` Ina magnetically-operated device, a source of magnetomotive force, a magnetic structure derlning. a magnetic pathr having a non-magnetic gap for magnetic` nux produced by said source, saidy magnetic structure including a magnetic polar plateV having a surface abutting said gap, the polar plate having an aperture communicating with the gap, a magnetic armature disposed substantially in said aperture in spaced relationshiprelative to the walls oi the aperture, means mounting the magnetic armature for .movement relativev to.- the polar plate about an axis towards and from the gap, the gap between the` polar plate, and the armature being greater at points a substantial distance from the axis than at points closer to the axis, and translating means responsive to movement ofl the armature relative tothe polar plate, said mounting, means comprising a resilient ribbon disposed in a plane transci verse to said axis, the 'ends of the ribtonbemg secured to the polar plate and to the armature respectively adjacent to said axis.V v

8. 1n a magnetically-operated device, av source of magnetomotive force, 'a magnetic structure defining a magnetic path having a non-magnetic gap for magnetic flux produced by' said source', said magnetic structure including a magnetic polar plate having a surface abutting said gap, the polar plate having an aperture communicating with the gap, a magnetic armature disposed substantially in said aperture in spaced relation# ship relative to the Walls of the aperture, means mounting the magnetic armaturel for Vm(' i'verne'nt relative to the polar plate about an axis' towards and from the gap, said gap being Vunobstructed in a predetermined direction, whereby a magnetic body may be passed through the gap in saiddirection, said polar plate substantially completely surrounding the magnetic armature in a plane parallel to said direction, and translating means responsive to movement of the armature relative to the polar plate.

9. In a magnetically-operated device, 'a source of magnetomotive `force, a magnetic structure defining a magnetic path having a non-magnetic gap for magnetic flux produced by s'aidl source, said magnetic structure including a magnetic polar plate having a surface abutting? saidgap", the polar plate having an aperture communicating with the gap, a magnetic armature disposedsubstantially in said aperture in spaced relationship relative to the Walls of the aperture, means mounting. the magnetic armature for movement relative to the polar plate about an. axis towards and from the gap, said gap beingv unobstructedy in a predetermined direction, whereby a magnetic body may be passed through the gapin said direction, said polar plate substantially completely surrounding the magnetic Iarma-ture in a plane parallel to said direction, a non-magnetic mem',-Y ber interposed between` the magnetic armature and the gap, said member being securedtothe polar plate to cover said aperture, and. a cover secured to the polar plate' to provide a substantially complete enclosure 'for the translating means, said enclosure being defined in part by the cover, the member and the polar plate',.and translating means responsive to movement oi? the armature relative to the polar plate.'V

CO'NWELL SAVAGE;

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